Invisible radiation, detection, and utilization



B. B. BRYANT April 9, 1935.

INVISIBLE RADIATION, DETECTION, AND UTILIZATION Original Filed Feb. 4, 1931 Patented Apr. 9, 1935 c v 1,997,356.

Beryl B. Bryant, Brooklyn, N. Y.

Application February 4, 1931, Serial No. 513,393

Renewed August 30, 193% r 6 Claims. (Cl. 179100.3)

This invention relates to the recordation of substantially direct proportion to the square of audio frequency modulations and more particuthe distance. larly to a method of recording voice modulations The intensity of penetration of this type of p n a film. radiation is inversely proportional to the square A major object of the invention is to provide of the distance and is determined by a number 5 a new and improved method of recording on of factors, such as the velocity of the cathode film, or other suitable receiving media, audio stream, the degree of abruptness of arrest of frequency modulations of greater clarity and dethe electrons of the cathode stream and the tail than heretofore, and particularly one which atomic characteristics of the ta get.

1 largely overcomes the difliculties of inhalation or Because of the characteristics of this type of 10 other disadvantages inherent in transmission eyrit d es t, 88 do th light y Present the and/or recordation by means of visible light difficulties of halation so typical of the visible I rays. rays,

Another object is to provide a novel method The p sent nve Considered broadly,

of nonhalation recordation of audio frequency therefore, comprehends the concept of modulat- 15 modulation. ing or controlling the emissivity of this type of Another object is to provide a. novel method ray by the electrical frequencies which 8If? to and apparatus of recording electrical frequencies be detected, indicated or reeo d da e y on photographic material. the concept is susceptible of a wide range of A further object is to provide a novel type physical embodiments. Modulation of the emit- 20 of oscillograph for the recordation of electrical ted invisible rays may be done in a variety of frequencies. manners, in which the frequency to be measured,

Yet another object is to provide, a new motion detected or recorded may be used either directly picture film upon which are recorded audio frea d diat y o indi y a d immediately 5 quency modulations. with any degree of amplification or diminution.

. A further object is to provide a new method Cons de ed mo Sp fi y, the invention and apparatus for the observation and measurecomprehends the provision of a generator for the ment of electrical frequencies. invisible rays, the efliuent stream of the invisible With these and other equally important object rays of which are governed or controlled or mod- 39 in view, the invention comprehends the utilizaed according to the voice current input into tion of the invisible spectrum of from approxithe Sy mh S r a Of invisible y 50 mately the 42.45 to the 60th octaves of the freified are then direc ed onto a movin fi m f quency spectrum which are modulated in accordphotographic material and the exposure of the once with the voice current or other frequencies fi m s de m n d y the intensity of the emitted which are to be measured, detected or observed. y and the Speed of the Rays of the above designated character whi h In order to more clearly describe the invention, comprehend the well-known soft ltr l t, a diagrammatic illustration of an apparatus emhard ultra-violet, soft, characteristic,secondary, hodying the Principles thereof s Shown in the hard, ultra 'X-rays, and gamma radiations accompanying d w 40 X-rays, have substantially different character- The apparatus-Shown in the drawing may, for 40 isti'cs from the visible r The rays in question general considerations, be considered as embodyare invisible to the eye, are. not reflected by a ing an electrical organization connected to a polished surface and are not refracted by priscafimde Flectmn emitting elen'fent; an matic means or other ocular means. They are cal system m which the output 18 mdu1ated,m not deflected by an electric or magnetic field terms of the voice current or otherfrequencies 45 and hence do not carry an electric charge. Like whch are measutred' ii fir or lfcorded;

an a con 0 ng sys em .w c opera es upon 23:23:: izf ais f if fiz g ifi ggi? the emitted cathode stream and through this means varies the character of the emission of 5 ductwlty to g e thrqugh wh1ch.they a the X-rays. The controlling system is properly 50. These rays travel in straight lines from the point associated with the modulating system so that of i f and because their Very hlgh the emission of the X-ray is controlled in acfrequencies may penetrate opaque substances and cordance with th modulations impressed upon may be used to magnify objects many times their th input d, natural size. This magnification power is in To more clearly explain the invention a pre- 2 ferred embodiment of it is shown in the drawing and will be described hereinafter. This, however, is given merely for the purpose of exempliflcation and is to be considered in a comprehensive and not a restrictive manner, for equivalent combinations and sub-combinations will readily suggest themselves to those skilled in the art. For example, in the preferred modification a transformer current that is rectified and filtered is used to set up the desired high potential difference necessary for the emission of the X-rays. By employing a transformer alone an alternating sinusoidal wave is produced, the inverse part of which is suppressed or rectified so as to produce a uni-directional pulsating current. In lieu of this a large induction coil may be used. The frequency in the case of the transformer alone or the induction coil should be as great as possible to promote cleamess of image although it is not necessary. to the function. The relative advantages and disadvantages of these two types of systems are well known to those skilled in the art.. (The induction coil gives a more penetrating ray and has a desirable high heat-penetration factor. The transformer, on the other hand, provides a relatively large proportion of soft ray many of which do not penetrate the walls of the tube, and has a heat penetration factor which is not as desirable as in the induction coil method.) These and other factors of the Xray tube are well known and hence a wide latitude-of choice in which these factors are governing is open to those operating under the principles of the invention. The description hereinafter, therefore, is to be considered as illustrative of one typical embodiment and not as the exclusive and sole manner of incorporating th: features of an invention in an operable appa- 18. 115.

The apparatus considered more specifically comprises an X-ray tube lwhich may be constructed largely of lead glass, or other suitable material which is opaque or substantially opaque with respect to X-radiation. This tube is provided with a window 2 suitably fitted into the main portion of the evacuated envelope i and is composed of 'a material such as quartz, tourmaline or fluorite to permit transmission of the high frequency radiation with minimal absorption. If desired, this window may be composed of a metal such as copper, beryllium, aluminum grueven thin sheet steel in the case of high power es. Fitted within the envelope is an anti-cathode 3 composed of a suitable metal, preferably of high atomic density such as platinum or tungsten. For some purposes it is required that the element 3 be of low atomicdensity with high infusibility. In the present embodiment tungsten is preferred because of its high infusibility and thermal conductivity. Platinum, of course, may be employed; to advantage; this has a higher radiation power than tungsten but is more susceptible to sputtering and is more-fusible than tungsten. The tungsten target, which is pre-' ferred, is set at apreferred angle of 45 to the path of the'cathode stream, or may be placed at any angle. The tungsten or platinum may be of any thickn and-is embedded in a copper block 6 to increase the quantum or mas of the metal andthereby'diminish the tendency to rise in temperature. This block is fitted with a-copper tube or rod 5 whioh'projects outside the tube and is fitted at its end with any suitable type of heat radiating means t. The tube or rod 5 is directly" to emit trolling the intensity of fitted into the evacuated envelo e through a feather edge or other suitable seal 1 to prevent fracture due to thedifferential expansion and contraction of the glass and the metal.

The target or anti-cathode, as is known, serves as the main anode of the X-ray tube and is the element which serves to abruptly impede or arrest the cathode stream, at which point of arrest the X-ray or invisible radiation is generated or pro-" duced. Inasmuch as the fraction of the energy of the cathode stream which is emitted as X-radiation increases with atomic weight of the target, materials of high atomic density are employed. The surface extent of the target is determined by the amount of power applied to the electrodes and by its distance from the electron emitting electrode.

The envelope is formed'with an enlarged base the tube is constructed of high dielectric glass.

Obviously in lieu of the A battery I! any other suitable heat generating means may be employed. For example, the filament l0 may be connected to the A. C. line through a step-down transformer and the current rectified andifiltered in the manner well known, or the transformer may be used alone in some instances where constant emission is not required.

The element It) is employed to heat an electron emitter element It. While on the drawing a separate electron heating element is shown, vious that this element itself may be employed the electrons of the cathode stream. The cathode or electron emitter Is of the Wehnelt oxide coated type is formed in substantially drum shape and is provided at its upper portion with an aperture or diaphragm it. The internal surface of the cathode is coated with oxide coatings or any other materials which are c racterized by a facile electron emission. The aperture or diaphragm in the upper portion of the cathode is provided for the purpose of conthe electrons which are emitted from the internal walls While this element is shown as of drum shape, it manifestly may be made up of any other form or from any other suitable material. For example, instead of applyi g aninternal coating of oxide on the drum this element may be made up in the form of a wire filament.

The cooperation of the elements It and M will have been appreciated from thisdescription. The filament it heats the electron emission elements Itv up to the emitting temperature. The aperture in the upper section of the cathode serves to direct the electronic or cathode beam and to control the electronic intensity. The cathode may besuitably supported upon the base of the en-' velope as by the element It. The cathode is connected by a use. It to a high voltage rectifier system-to be more fully describedfor the purpose lt is 0b-' of the element.v

mam

lated frequencies which are to be measured.. The function of the element l9, or its equivalent,

is to direct and control the intensity of the cathode or electronic stream. The control exercised-- by the element I4 is supplementedby the control element 20. The element 20, when included in the tube, assists in the control and direction of the cathode stream and in addition serves asa. control element when the device is employed as a high frequency generator. In this use it modi fies the velocity of the cathode stream and functions to reduce the power requirements and to inexclusive use to which the assemblage may be put is that of recording audio frequency modulations upon a film. The similarity of this method and the common relationship of the fundamental factors to the other types of recordation v pedance matching transformer 23.

of. indication will readily suggest other specific uses to those skilled in the art. The input of the system comprises a microphone or other frequency generator or electrical converter 2! which picks up the sound or other waves to be recorded. The electrical frequencies corresponding to the sound or other waves are fed into'and amplified by the cascade amplifier system indicated generally by the numeral 22. This is shown as comprising a two-stage transformer coupled amplifying system, but it will be readily understood that any other desired type may be employed and any desired extent of amplification may be secured. The output of the amplifier system feeds the amplified electrical frequencies into the im- This trans former has its secondary winding 24 connected across the cathode l4 and the modulating anode IS. The Heising system of modulation may be employed when using the tube as a generator by connecting the anode of the amplifier direct to the element 4 making provisions for the proper potential supply of the output amplifier tube and the generator tube through a common anode inductance without impairment or attenuation of the frequencies used to modulate the generator. With the method shown this is done by connecting the anode I9 through the lead 25, which passes through the insulation tube 26, adjacent one end of the secondary transformer, and the cathode through the lead l8 adjacent the other end.

Power may be supplied to the system through an A. C. line through the high voltage rectifier 26,

' 'whichis shown-as of conventional construction and needs no extensive description. In some in-' stances the filter circuit is modified or padded with an impedance net work to prevent short circuiting of the modulating frequencies as is known by those skilled in the art. Preferably the rectifier is supplied with heating current for the" filament through a secondary transformer winding section. The rectified uni-directional current, which is filtered and smoothed when re- ,quired, supplies sufiicient potential between thecathode l4 and the anode I! for a proper control of the cathode stream. on this impressed potential is superimposed modulated freguencies from the input circuit through the transformer 23 so that, in a manner well known, the intensity of theelectronic stream or cathode stream or beam is modulated or varied directly inaccordance with the input frequencies modulated in accordance with the frequencies which are to be recorded.

Numeral 21 indicates a high voltage generator or anyother type of high voltage frequency generator-such as a magnetron, negatron, dynatro-n, piio-dynatron Vreeland generator or other type as desired, the negativeof which is conductively connected, through the lead28, to the auxiliary anode IS. The positive side of. the high voltage generator is connected through the oscillatory circuit 29 and the lead 30 to the main anode 4.

The auxiliary control element 20, which may be functionallyconsidered as a grid sleeve, is connected, through the conductor 3| carried through the-tube by means of the insulating tube 32, to one side of the inductance 33.

28 to the control electrode IS. The main modulating anode l9 and the grid control element, are both preferably of conoidal shape and are constructed of suitable material so as to con- The other end of this inductance is connected through the line centrate the cathode stream into a beam and I to vary the intensity of this streamin accordance with the imposed modulating potentials.

From the description thus far it will be seen" controlanodes l9 from the amplifier and the I constant potential source 26 and by the suitably chosen potentials of the grid sleeve 20, results in the emission of an X-radiation from the focal point on the target through the transmitting plate 2. This radiation stream passes through the plate 2 and impinges upon the screen 34. This screen is provided with a. slot or aperture 35 which is centered with respect to the center of thetarget or anti-cathode d. The photographic film 36 is fed past the aperture 35 on a suitable guide 31. The movement of the film in front of the screen is effected by a suitable sprocket or other drive mechanism, comprising the rollers 38,

38 and 40. v

The film employed for the present type of recordation is preferably more, opaque or dense than the materials ordinarily employed in films, although the latter are successfully used. It has been found that the greater the .opaqueness or denseness of the. film the better the modulation. In the use'of the present invention therefore it is preferred that the einulsion of the film contain a dense metallic salt such as lead or barium sul-. phate, or other materials which are capable of absorbing this type of radiation, and of soluble chemical reduction as the silver bromide salts in the ordinary photographic chemical reduction system, therefore, may

response to the the microphone ii are amplified in the cascade amplifier 22 and these are impressed in the manner described upon the control electrodes so as to vary the quantum or intensity of the emitted stream of electrons in accordance with the impressed signals. The variation in .the intensity of the cathode stream results in a corresponding variation in the intensity of the emitted X-radiation, and this in turn correspondingly and proportionately modifies the degree of exposure 0 the photographic film passing in front of the screen 34. Assuming a given regulated speed of movement of the film 82, the exposure of the film then corresponds to the signals impressed at the input end of the modulating system.

The preferred embodiment described herein comprises the association of an audio frequency controlled system with an X-radiation generator, the emanation of the X-radiation from which corresponds to the audio frequency modulations to be recorded. It will be appreciated that this system is of particular value and utility in the motion picture industry and in phonographic reproduction. Due to the non-halation characteristics of the invisible rays and to the accurate and true impressed signals, phonographic strict response is assured.

be employed for animproved type of orthophonic recordation. The film having the exposed portions corresponding to the tonal efiects impressed on the input system may be recorded in a phonograph, the speaker of which is operated from this type of filni.

The system is of peculiarly effective utility in the motion picture industry. The x-radiations may be concentrated or focused upon any desired large or small section of the motion picture film so that the exposures of figures and of the oscillations corresponding to voice modulations may be simultaneously made on the same film. If desired, the voice modulations may be recorded on the thin strip of separate film and the recordation unit synchronized with the motion picture camera. After the completion of a picture or section of a picture the two films may be associated together for simultaneous reproduction.

It will be appreciated from the description given herein that the invention is not limited in use in the, phonographic or photographic fields, but is of rather wide utility. For example, with the apparatus shown in the drawing, any factor which can be transmuted' by microphonic or similar action into a corresponding variation in electrical output and which output can be made to vary the electrical characteristics. of'the control electrodes can be detected and/or 'measured and/ or recorded by the present system with suitable modifications in the apparatus. Thus, for example, as pointed out hereinbefore, the element 2| may be any.type as a hot wire microphone. When such hot wire microphone is employed it may be utilized, as will be understood by those skilled in the art, as a high temperature pyrometer inasmuch as the electrical effect impressed on the input circuit will be the function of the temperature. Similarly, the element 2|, instead of being a microphone, may be a photoelectric cell, in which case the output of the X-ray tube will be a function of the light intensity to which the photoelectric tube is subjected. In short, the invention is susceptible for usein any field wherein it is desired to indicate or record any type of effect which may reproduction of of electrical converter, suchtwo similar or dissimilar Therefore, while a specific physical embodif ment of the invention has been disclosed, it is to be understood that this is given merely as one method of embodying the principles herein disclosed in a physical apparatus for the purpose of producing an improved physical result. The

invention is conceived to comprehend all the mechanical and electrical embodiments and ramifications which operate in an equivalent manner to produce a comparable or similar result.

I claim:

l. A recording apparatus comprising a generator of radiations, a control electrode operable upon the electronic stream of the generator, and audio responsive means associated with the control electrode to eiiect a variation in the intensity of the electronic stream, and a second control electrode, connected to ahigh. frequency generator and so positioned as to operate on the electronic stream to further vary the intensity thereof whereby the output of the generator is varied in accordance with the input audio frequency waves.

control electrodes interposed between an electron emitting element and an electron arresting element, means to connect one of said electrodes to a high frequency generator, and means to connect the said input circuit to the other control electrode of the generator so as to vary the emission of the invisible radiations in accordance with variations in the frequencies impressed on the input circuit and in accordance with the potential applied by the high frequency genera- 3. A method of recording sound comprising transmitting sound waves into electrical energy, generating invisible radiations by the arrest of a high velocity electronic stream; varying the emission of the invisible radiations by utilizing the said electrical energy to modify the characteristics of the electronic stream then intensifying the modification of the stream by subjecting it to additional accelerating potential and photographically recording the variation of the emittedv invisible radiation.

4. A method of indicating sound waves comprising transmuting the sound waves intoco'rresponding electrical energy, generating invisible radiations by suddenly arresting an electronic stream, modifying the intensity of the invisible radiations generated v electrical energy to act upon the electronic stream and further increasing the intensity of the invisible radiations by subjecting the electronic stream, as modified by the transmuted electrical energy and additional potential independent of transmuted electrical energy.

5. A sound recording system comprising a microphonie device and an amplifying circuit for the variableenergy generated by the device; a generator of invisible radiations, the generator comprising an electron emitting element, a tarthe said by causing the transmuted before arresting, to an crease the intensity ofthe electronic stream and to concentrate such stream into a more-concentrated beam; a second control electrode encompassing the said concentrated beam, interposed between the first said control electrode and the target and connected to a high frequency generator and operating upon the audio modulated electronic stream to increase its intensity and to concentrate the stream; and means comprising a sensitized film to record the modulated invisible radiations emitted from the target.

'6. A sound recording system comprising a pickup device and an amplifying circuit for the variable energy generated by the device; a generator ofinvisible radiations of the X-ray type, such generator comprising an elech'on emitting elemerit, a target of high atomic density interposed in the path of the electron emanating from the electron emitting element, a control electrode in= terposed between said element and the target and connected to the output of the amplifying circuit, said controlelectrode enclosing the stream of electrons emitted from the electrode emitting element and functioning to increase or decrease the intensity of the electronic stream in accordance with the energy impressed thereon from the amplifying circuit; a second control electrode encompassing the modulated beam and interposed between the first ccntrol electrode and the target but said second control electrode being connected to a high voltage source and functioning to increase the intensity of and concentrate the. electronic stream before such stream is impinged uponthe target, and means comprising a sensitized film positioned within the path of the invisible radiations emitted from the said target. 20

BERYL B. BRYANT. 

